Sulphur purification



' NdDrawing.

V 7 Various absorbing Patented Mar. 29, 1932- MARK. sHonLn,

sumfntm; runrrrca'rrou Application and spruce,

This invention relates to sulphur and methods of improving its qualityand more particularly to the removal of certain im purities therefrom torender it more suitable for agricultural purposes.

In the purification of fuel gases (including coal gas, water gas, oilgas, and natural gas), hydrogen sulphide, hydrogen cyanide and otherimpurities are removed by an absorbent liquid, and sulphur is liberatedwhen the thereby fouled liquid is aerated or actified for the purpose ofregenerating it for further use. Examples of such purification processaes are described in copending applications Serial No. 146,569 and SerialNo; 146,571, filed November 5, 1926, and Serial 170.173; 614:,filedMarch 7, 1927. V Z

liquids are mentioned in these applications, as for instance solutionsof alkaline earth metal compounds of metals of thetin group,'orsolutions of thio-arsenic compounds of alkali metals, or alkalinesolutions of compounds ofmetals of the tin group. Among these may alsobe included the well known alkaline solutions containing metalliccompounds, such as iron oxide, nickel sulphide, and the like, which areused in cyclic gas purification processes for sulphur which is removedin elemental form'in h the actification stage.

An object of this invention is to provide a free flowing sulphur dustparticularly from sulphur obtained in the above and simi lar processes.7

A further object is to prepare an improved sulphur which is veryeffective as an insecti cidal, germicidal or fungicidal agent.

A still further object is to provide a process for preparing a sulfur.free from ingredients which are harmful to cultivated plants.

The crude sulphur separated by filter presses or other means as aby-product from the above gas purification a water solution of sodiumsalts, principally thiosulphates and thiocyanates and in some casesarsenates and arsenites. The thiocya- A preferred method ofprocesses,contains about 40 to 50% of sulphur. The balance is 1929.Serial no. 358,426.

have adestructiveeffectonleaveszand twigs. 7 It 1s therefore essentialto remove, or render i these constituents harmless I to cultivatedplants. Besides having the destructive property, the thiocyanatespresent inthe foul absorb ingliquid mentioned above and adhering to thesulphur, arealso very" hygroscopic and in prep aring a :dry dustingsulphur, ence of 'these substances is very undesirable. Sulphur obtainedin, the above gas puriiication processes'is partially'of colloidaldimensions and has a considerable adsorptive power towards the saltspresent and it is diflicult to remove all-the salts by a simple washmg.1

In the processof this invention, both the adsorbed thiocy a nates aswellas thosewhich are freely intermingled with the sulphur are I 7h I thisinvention, the b'Y-PIOdIlCt"igEtS-llOllSG sulphurrendered harmlessji"llnv accordance withfthe process of is mixed'with water to form aslurryand a.

reagent is added wliichlformsan insoluble precipitate with thethiocyanates'. The insolr,

uble thiocyanates formedmay beremoved, as

by settling, or they maybe permitted tore- -main'-in thesulphur. r v

' Examples ofreagents which maybe used for precipitating thethiocyanates, are salts of such metals as copper, silver, lead,androth-. vers. Preferably the more soluble salts are used, suchas thenitrates or acetates, ofIa-ny oflthe metals mentioned, "ora sulphate asin the case of copper.- These reagentsmay be used in solutions orm dryform.

isas follows house sulphur The sulphur pastefas 1t comesfrom; the

with water to form a slurry gas plantis mixed 7 to 10% of sulphur. The

containing about the pres purifying a -gas-.

i UNITED STATES PATENT @FF'ICE.

or MOUNT LEBANON 'row vsmrgetrnennivrcouiv'ry, r NNsYL- I VANIA,ASSIGNOR Towns xorruns COMPANY, A CORPORATION OEDELAWARE V temperatureof the water'is kept. above 709 F. or preferably around 100 F. a

'This slurry is "filtered and-the moist sulphur cake is repulpeda'withwater; at about thesame temperature to form a slurry of the sameconsistencyas the above. l ":5: QA small amount of copper sulphate50111- ti-oii His" new addedlto- .the slurry and miXed therewith and thethiocyanates are precipiimpuritieswhich pounds to those which tated intheform of cuprous thiocyanate. The amount of precipitating reagentadded is preferably slightly in excess of the amount to change all thethiocyanates from to insoluble or from harmful comre harmless to culti-'vate'd plants; .The treatedsulphur-is'sepae rated out by filtration andif a sul hur paste i-sdesired the material is ready or use.

needed soluble If a dusting sulphur is wanted,- the-treat sulphurisdri'ed at a temperature preferably not exceeding 180 F. V p r r In theprocessof this invention,"a. by-product gas-house sulphur of highquality is pro: duced. The process is simple and yet very effective andthe treated sulphur is free from' have the objectionable pr0pertiesmentioned above.

I claim as my invention: V 1; In a process of purifying sulphurcontaining thiocyanates, the step oftreating sulphur to. change solublethiocyanates present the second slurry at about 1 009 copper sulphate tochange thiocyanates present in the sulphur to cuprous thiocyanate,

and drying the sulphur thus treated.

8. A free-flowing sulphur dust containing water-insoluble thiocyanates'1 9. A asa by-product in the purification of ,fuel gases, which processcomprises mixing the said. by product sulphur with water to disin the;sulphur mass; to. insoluble thiocy-anates.

2. In a process of treating byi-prodjuct gas-V housesulphur-,;thestep oftreating the sulphur with a solution of copper'sulphate to change thethiocyanates present in-the sulphur, mass, to'icuprous thiocyanate.

= 3. A process oftreating sulphur containing 1 I thi-ocyanates, whichcomprises mixing f the sulphur with water and adding to the mixture I areagent which will change ,thiocyanates present in the mixture andrender the thio cyanates harmless 't'o-xclultivated plantsw 4. A processof treating sulphur obtained -as a by-productin;thepurificationo of fuelgases,- which comprises-mixing the by-product sulphurwithwater andaddinga salt of a metal; which willreact with thiocyanates present inthesulphur to-form insoluble thiocy an'ate;

as a by-product in the purification of fuel gases, which comprisesmixing the by -prod- "uct sulphur with waterand adding copper sulphateto changethiocyanates present in the sulphur to cuprous thiocyanate.

6. A process of treating sulphur-obtained as a by-productin.the'purificationoffuel gases,:which comprises mixing the by-productsulphur with Water, keeping the'temperature ofthe water at about 100'F'.,- removing V V 5. -A process of, treating sulphur obtained v I thesolid matter fromthe liquid,adding-:water to thesaid solid matter,\andadding a salt of a metal which will react with thiocyanate T present inthe sulphur, to form insoluble thiocyanate. V a

7. A process of treatingsulphur obtained as :a. byeproductin, thepurification of; fuel .gases,rwhich comprises mixing the by-productsulphur with water to form a slurry, keep-- ing the temperature of the,Wat'era-t about 1 100 F., removing the solid matter :fromthe liquid,adding water. to theysaidsolid zrnatter toform a slurry,- keeping thetemperatureof F, adding areharmless to cultivated V process of treatingsulphur obtained vto the resulting V

